scholarly journals Satellite Intensities in Photoelectron Spectroscopy and Electron Momentum Spectroscopy-Synchrotron Radiation Studies of Argon 3s and Xenon 5s Photoionisation (hv - 60?130 eV)

1986 ◽  
Vol 39 (5) ◽  
pp. 565 ◽  
Author(s):  
CE Brion ◽  
KH Tan
Keyword(s):  
Synchrotron Radiation ◽  
Photon Energy ◽  
Photoelectron Spectroscopy ◽  
Impulse Approximation ◽  
Main Line ◽  
Magic Angle ◽  
Electron Momentum ◽  
X Ray ◽  
Plane Wave Impulse Approximation ◽  
Electron Momentum Spectroscopy

Binding energy spectra for the main line, satellite lines and associated double ionization continuum for argon 3s and xenon 5s photoionisation have been measured in the photon energy range 60-130 eV using monochromatised synchrotron radiation and magic angle photoelectron spectroscopy. In particular the ratio of satellite to main line intensities has been investigated and compared with the results of earlier experiments using X-ray and ultraviolet photoelectron spectroscopy as well as with recent measurements by electron momentum [i.e. binary (e,2e)] spectroscopy. The results of the presently reported photoelectron measurements show that the satellite intensity relative to that of the main ns -1 line increases with increasing photon energy and approaches the value given by electron momentum spectroscopy. These findings are contrary to predictions based on recent calculations of photoelectron intensities. The present work lends support to the direct interpretation of satellite intensities (pole strengths or spectroscopic factors) in binary� (e, 2e) spectroscopy using the plane wave impulse approximation. The need for improved calculations of photoionisation intensities as well as further photoelectron measurements in the X-ray region is stressed.

scholarly journals Application of DFT and EMS to the Study of Strained Organic Molecules

1998 ◽  
Vol 51 (4) ◽  
pp. 707 ◽  
Author(s):  
W. Adcock ◽  
M. J. Brunger ◽  
M. T. Michalewicz ◽  
D. A. Winkler
Keyword(s):  
Wave Function ◽  
Density Functional ◽  
Impulse Approximation ◽  
Basis Sets ◽  
Functional Theory ◽  
Electron Momentum ◽  
Plane Wave Impulse Approximation ◽  
Electron Momentum Spectroscopy ◽  
Momentum Distributions ◽  
Self Consistent Field

Electron momentum spectroscopy (EMS) studies of the valence shells of [1.1.1]propellane, 1,3-butadiene, ethylene oxide and cubane are reviewed. Binding energy spectra were measured in the energy regime of 3·5–46·5 eV over a range of different target electron momenta, so that momentum distributions (MDs) could be determined for each ion state. Each experimental electron momentum distribution is compared with those calculated in the plane wave impulse approximation (PWIA) using both a triple-? plus polarisation level self-consistent field (SCF) wave function and a further range of basis sets as calculated using density functional theory (DFT). A critical comparison between the experimental and theoretical momentum distributions allows us to determine the ‘optimum’ wave function for each molecule from the basis sets we studied. This ‘optimum’ wave function then allows us to investigate chemically or biologically significant molecular properties of these molecules. EMS-DFT also shows promise in elucidating the character of molecular orbitals and the hybridisation state of atoms.

scholarly journals A Procedure to Determine Dyson Orbitals from Electron Momentum Spectroscopy: Application to 1,2-Propadiene, 1,3-Butadiene, Cyclopropane and [1.1.1]Propellane

1998 ◽  
Vol 51 (4) ◽  
pp. 691 ◽  
Author(s):  
R. J. F. Nicholson ◽  
I. E. McCarthy ◽  
M. J. Brunger
Keyword(s):  
Inverse Method ◽  
Impulse Approximation ◽  
Reaction Model ◽  
Electron Momentum ◽  
Plane Wave Impulse Approximation ◽  
Molecular Systems ◽  
Hartree Fock ◽  
Fitting Procedure ◽  
Electron Momentum Spectroscopy ◽  
Measured Momentum

We employ a numerical inverse method of extracting the target-ion overlap, or normalised Dyson orbital, directly from experimental electron momentum spectroscopy data by using a quantum- mechanically constrained statistical fitting procedure. This method is used in conjunction with the previously verified, for molecular targets, plane wave impulse approximation (PWIA) reaction model. The present procedure was applied to previously measured momentum distributions (MDs) for the 2e′ and 1e′ valence orbitals of cyclopropane, the 7ag orbital of trans 1,3-butadiene, the 2e orbital of 1,2-propadiene and the 3a′1 orbital of [1.1.1]propellane. We note that this is the first extensive application of the present method to organic molecular systems. In each case the derived normalised Dyson orbital provided a superior representation of the experimental MD than did the corresponding Hartree-Fock orbital. The ramifications of this result are discussed in the text.

Electron momentum spectroscopy experiments and calculations for the production of excited states of He+ and

1996 ◽  
Vol 74 (11-12) ◽  
pp. 748-756 ◽  
Author(s):  
N. Lermer ◽  
B. R. Todd ◽  
N. M. Cann ◽  
C. E. Brion ◽  
Y. Zheng ◽  
...  
Keyword(s):  
Excited States ◽  
Cross Section ◽  
Cross Sections ◽  
Impulse Approximation ◽  
Final State ◽  
Electron Momentum ◽  
Plane Wave Impulse Approximation ◽  
Highly Sensitive ◽  
Electron Momentum Spectroscopy ◽  
Explicitly Correlated

The (e,2e) cross-section for transitions to the n = 2 final state of He+ and the 2sσg, final state of [Formula: see text] have been measured, relative to the cross-section for the transitions to the respective ground state ions, using a highly sensitive momentum dispersive multichannel electron momentum spectrometer. The experimental results for He are compared with plane wave impulse approximation (PWIA) cross-section calculations carried out using two previously published GI wavefunctions and also with two cross-section calculations based on explicitly correlated wavefunctions with energy errors of less than 10 nHartree. The H2 results are compared with calculations by J.W. Liu and V.H. Smith Jr. (Phys. Rev. A, 31, 3003 (1985); erratum: Phys. Rev. A, 39, 3703 (1989)). For both He and H2, significant differences are observed between the measured relative cross-sections and those calculated using the PWIA. While the measurements for He differ from previous work, the results for H2 are consistent with some earlier measurements.

scholarly journals Electron Momentum Spectroscopy

1986 ◽  
Vol 39 (5) ◽  
pp. 587 ◽  
Author(s):  
IE McCarthy
Keyword(s):  
Impulse Approximation ◽  
High Electron ◽  
Final States ◽  
Final State ◽  
Structure Information ◽  
Plane Wave Impulse Approximation ◽  
Ion Structure ◽  
Spectroscopic Factors ◽  
Electron Momentum Spectroscopy ◽  
Energy And Momentum

For sufficiently high electron energies (greater than a few hundred eV) and sufficiently low recoil momenta Oess than a few atomic units) the differential cross section for the non-coplanar symmetric (e,2e) reaction on an atom or molecule depends on the target and ion structure only through the target-ion overlap. Experimental criteria for the energy and momentum are that the apparent structure information does not change when the energy and momentum are varied. The plane-wave impulse approximation is a sufficient description of the reaction mechanism for determining spherically averaged squares of momentum-space orbitals for atoms and molecules and for coefficients describing initial- and final-state correlations. For mainly uncorrelated initial states, spectroscopic factors for final states belonging to the same manifold are uniquely determined. For molecules, summed spectroscopic factors can be compared for different ion manifolds. For atoms, summed spectroscopic factors and higher-momentum profiles require the dist~rted-wave impulse approximation.

Band Alignment of Al2 O3 Layer Deposited NO and SO2 Exposed (001) H-Diamond Heterointerfaces Studied by Synchrotron Radiation X-Ray Photoelectron Spectroscopy

2018 ◽  
Vol 215 (22) ◽  
pp. 1800237 ◽  
Author(s):  
Niloy C. Saha ◽  
Kazutoshi Takahashi ◽  
Masaki Imamura ◽  
Makoto Kasu
Keyword(s):  
Synchrotron Radiation ◽  
Photoelectron Spectroscopy ◽  
Band Alignment ◽  
X Ray

EPITAXY OF ULTRATHIN CoO FILMS STUDIED BY XPD AND GIXRD

2002 ◽  
Vol 09 (02) ◽  
pp. 937-941 ◽  
Author(s):  
P. LUCHES ◽  
C. GIOVANARDI ◽  
T. MOIA ◽  
S. VALERI ◽  
F. BRUNO ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Lattice Constant ◽  
Photoelectron Spectroscopy ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
Direction Parallel ◽  
X Ray ◽  
Photoelectron Diffraction ◽  
Rocksalt Structure ◽  
Plane Lattice

CoO layers have been grown by exposing to oxygen the (001) body-centered-tetragonal (bct) surface of a Co ultrathin film epitaxially grown on Fe(001). Different oxide thicknesses in the 2–15 ML range have been investigated by means of synchrotron-radiation-based techniques. X-ray photoelectron spectroscopy has been used to check the formation of the oxide films; X ray photoelectron diffraction has given information concerning the symmetry of their unit cell; grazing incidence X-ray diffraction has allowed to evaluate precisely their in-plane lattice constant. The films show a CoO(001) rocksalt structure, rotated by 45° with respect to the bct Co substrate, with the [100] direction parallel to the substrate [110] direction. Their in-plane lattice constant increases as a function of thickness, to release the in-plane strain due to the 3% mismatch between the bulk CoO phase and the underlying substrate.

Synchrotron Radiation Soft X-ray Induced Reduction in Graphene Oxide Characterized by Time-Resolved Photoelectron Spectroscopy

2015 ◽  
Vol 119 (23) ◽  
pp. 12910-12915 ◽  
Author(s):  
Chi-Yuan Lin ◽  
Cheng-En Cheng ◽  
Shuai Wang ◽  
Hung Wei Shiu ◽  
Lo Yueh Chang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Synchrotron Radiation ◽  
Photoelectron Spectroscopy ◽  
Time Resolved ◽  
X Ray
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